Track surfacing method

ABSTRACT

Ballast is compacted and the track is leveled simultaneously by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level.

ited States Patent Plasser et a1.

[ NOV. 18, 1975 TRACK SURFACING METHOD Inventors: Erma Plasser; Josef Theurer, both of Johannesgasse 3, Vienna, Austria, A-lOlO; Egon Schubert, Lainzerstr. 246/ 8,. Vienna, Austria; Klaus Riessberger, Paniglgasse 24, Vienna, Austria Filed: July 22, 1974 Appl. No.: 490,394

Related US. Application Data Division of Ser. No. 404,427, Oct. 9, 1973.

Foreign Application Priority Data Oct. 13, 1972 Austria 8816/72 US. Cl. 104/7 R; 104/12 Int. Cl. E01B 37/00 Field of Search 104/7, 8, 12

[56] References Cited UNITED STATES PATENTS 3,710,721 1/1973 Stewart 104/12 3,796,160 3/1974 Waters et a1 104/12 3,797,397 8/1971 Eisenmann et a1. t 104/12 3,807,311 4/1974 Plasser et a1 104/12 Primary Examiner-Lloyd L. King Assistant Examiner-Richard A. Bertsch Attorney, Agent, or Firm-Kurt Kelman [57] ABSTRACT Ballast is compacted and the track is leveled simultaneously by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level.

25 Claims, 21 Drawing Figures Patent Nov. 18, 1975 Sheet 1 of9 US. Patent Nov. 18, 1975 Sheet2of9 3,919,943

3/ 22 I5 I 29 I5 22 3/ U.S. Patent Nov. 18, 1975 Sheet30f9 3,919,943

U.S. Patent Nov. 18,1975 Sheet4of9 3,919,943

U.S. Patent N0v.18, 1975 Sheet5of9 3,919,943

ELIE-z... l4;

US. Patent Nov. 18,1975 Sheet60f9 3,919,943

U.S. Patent Nov. 18, 1975 S heet70f9 3,919,943

US. Patent Nov. 18,1975 Sheet90f9 3,919,943

TRACK SURFACING METHOD This is a division of application Ser. No. 404,427, filed Oct. 9, I973.

The present invention relates to improvements in a method surfacing a track consisting of rails fastening to ties resting on ballast.

In track surfacing, it has been proposed to impart at least substantially horizontal vibration to a track in a section wherein the ballast is compacted, particularly under the track ties and while the track is positioned at a desired level. In the leveled track, the ballast serves to absorb the forces to which passing trains subject the track. In view of the resiliency and wear of the ballast, the track level changes in the course of time. Therefore, the track must be leveled from time to time to achieve the desired grade, at which the track is fixed by tamping the supporting ballast under the ties.

Tie tamping forms an essential part of many known track leveling methods. In this operation, the ballast is compacted underneath the ties by pressure and vibration to the highest attainable degree to form as rigid a track support as possible. However, none of the known tamping methods has succeeded in fixing the track at a desired level sufficiently to resist depression by passing trains for long. Immediately after tamping, the track settles rather rapidly and this downward movement slows down with time. This phonomenon results from the fact that the tamping relocates the ballast pieces in new positions in which they are subjected to the vertical, static and dynamic loads of passing trains, leading to their wear and settling. Since the ballast does not settle uniforrnaly along the track, many deviations from a straight level soon appear.

An attempt has been made to improve the ballast compaction by subjecting the ballast to vertical vibrations transmitted to the ballast by the track rails and/or ties, or directly by vibratory surface compactors. However, it has not been possible to commercial operations to obtain a permanently fixed ballast bed in this manner. Similar lack of success has been encountered with vibrating the track solely in a horizontal direction.

In another known track correction method, the track section to be corrected is subjected to vibrations and is raised to the desired level. Subsequently, the ballast is tamped under the ties to fix the track at the raised level. This method has not been commercially used.

It is a primary object of this invention to provide track surfacing which results in a durable and more uniformly compact ballast support for the track ties. The track surfacing of the invention discounts the usual settling of the newly tamped ballast under the loads of trains passing thereover.

The above and other objects are accomplished according to the invention by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level to compact the ballast under the track ties and simultaneously position the track at a desired level. Any deviation of the track position from a desired level may be deteremined and the track pressed to the desired lower level.

Unexpectedly, the combination of the horizontal vibration and the downward pressure providess a ballast compaction which far surpasses the quality achieved with known track surfacing methods and equipment. During the ballast compaction according to the present invention, the ties are pressed into the ballast and this 2 vertical downward movement of the track into the compacted ballast is taken into account in determining the desired track level. In this way, the track surfacing actually simulates and discounts the subsequent train traffic so that the desired level will be maintained despite of it.

Since long used track usually has been pressed by the passing train traffic below the desired grade, it will be useful in such cases to raise the track above tis level and to tamp the ballast under the ties of the raised track before track surfacing is effected in accordance with the invention. When a newly laid track section is installed, this will not be necessary since such track is laid at a higher than desired grade and may then be directly leveled to the desired grade by means of the track surfacing of the present invention.

Throughout the specification and claims, the term substantially horizontal vibration means a vibration with a marked horizontal component extending transversely of the track elongation. Thus, the vibration may be produced in planes oblique to the horizontal plane as long as the resultant vibration has a marked horizontal component.

Preferably, the vibration has the same or nearly the same frequency as the natural or characteristic frequency of vibrations of the track, measured in a transverse direction, the frequency being, for instance, in the range of 8 to 13 cycles per second. This has the advantage that the vibrating force may be relatively small since the vibrated track section will be in resonance.

The track surfacing of this invention is very flexible and sensitive because it opens the way to a variety of controls. Thus, it is of particular advantage to determine the downward stroke required to press the track down to the desired level, i.e. the deviation of the track therefrom, to produce an error signal proportional to the deviation, and to control the frequency and/or the amplitude and/or the duration of the vibration and/or the force and/or the duration of the downward pressure in response to the error signal.

Controlling the force of the downward pressure on the track in response to the error signal has the best results, i.e. the track responds best to changes in the force of the pressure as far as track leveling is concerned. However, changing the vibration frequency and/or amplitude also has advantages. Combining and/or selecting the indicated controls enables the operator to adapt the operation to ballast beds of all types.

It is particularly useful to select the downward pressure force so that it corresponds to the order of magnitude of the train loads expected in traffic over the surface track section. However, since this would require very heavy surfacing equipment, it is advantageous to press the track down by a pulsating stress force. Such a stress may be a dynamic force and is, therefore, independent of the weight of the machine. In a preferred embodiment, the pressure force has a static and dynamic component, the dynamic component being an oscillating force whose amplitude does not exceed twice the static component of the pressure force. In this way, the pulsating stress will press on the track without lifting the apparatus off the track.

It is possible to effectuate track surfacing according to the invention stepwise or continuously as the apparatus advances along the track. In the latter case, it is useful to determine any deviation of the track position from the desired level continuously while imparting the horizontal vibration and downward pressure to the 3 track. This may be done, for instance, with the track correction apparatus described and claimed in US. Pat. Nos. 3,211,109 or 3,041,982. Since the abovedescribed controls make it possible to position the track at the desired level relatively rapidly in accordance with the inventon, the continuous method pro duces a very high efficiency.

The determinative operational parameters, such as pressure force, frequency and amplitude of vibration, and duration, may be controlled not only in response to an original error signal but also be a continuous error signal during te movement of the track to the desired level. Thus, it may be useful to increase the pressure force as the track approaches the desired grade since the compaction of the ballast increases correspondingly so that the ballast yields less and less to the downward pressure. In this way, the duration of the downward pressure may be decreased and the efficiency of the operation prportionally increased.

Also, the amplitude of vibration may be considerably reduced or the vibration may be totally stopped shortly before the track reaches the desired level so that the ballast pieces will not be unduly dislocated by vibrations at this level.

Since the downward pressure lodges the track ties within the ballast, the track surfacing according to the present invention also tends to fix the track stongly in its lateral position. Therefore, it will be most useful to line the track ahead of the track surfacing or in the range thereof.

In the apparatus used in the method of this invention, the arrangement and type of means for imparting a substantially vertical downward pressure on both rails of the track are of particular importance. The preferred pressure means are hydraulic rams and, to make a continuous operation possible, the rams are supported on a mobile apparatus and preferably are mounted in vertical alignement with rail engaging wheels to exert the pressure on the track by means of the wheels. Thus, with the proper pressure control for the rams, the pressure force may reach the magnitude of the weight of the apparatus.

To obtain different pressures along the track section in the surfacing zone, a plurality of hydraulic rams maybe spaced in the direction of track elongation and may be subjected to different pressures. In this manner, no special controls are needed to obtain a stepped change in the pressure force exerted upon the same track point as the apparatus advances continuously along the track. It is also useful to arrange a plurality of pressure means in a direction transverse to the track since different pressures applied to such means can take into ac- 1.

count any superelevation of the track or different track level errors at the two rails at the same track point.

Similarly, a plurality of vibration imparting means may be spaced in the direction of track elongation so that the vibration amplitude may be changed simply by switching on or off additional vibrators.

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain now preferred embodiments thereof, taken in conjunction with the accompanying drawing wherein FIG. 1 is a schematic side elevational view of an apparatus incorporating structures arranged and designed to carry out the method of this invention;

FIG. 2 is a like view of such an apparatus incorporating modified structures of the indicated type;

FIGS. 3 and 4 are schematic transverse sections of the apparatus of FIG. 2 along line IIIIII and IvIV, respectively;

FIGS. 5 and 6 are side elevational and top plan views, respectively, of an embodiment of an auxiliary car carrying the pressure-applying and vibrator structures used in the invention;

FIGS. 7 and 8 are transverse sections of the auxiliary car along lines VII-VII and VIIIVIII, respectively, of FIG. 6;

FIGS. 9 to 13 schematically illustrated various embodiments of structures for transmitting horizontal vibrations from the vibrators to the track;

FIG. 14 schematically illustrates an embodiment of a structure for transmitting horizontal vibrations directly to the track ties;

FIG. 15 is a circuit diagram of a control circuit for controlling the downwardly applied pressure in dependence on, or a function of, the position of the track;

FIGS. 16 and 17 are circuit diagrams of control circuits for controllig the frequency of the vibrations in dependence on, or a function of, the position of the track;

FIGS. 18 and 19 are circuit diagrams of control circuits for controlling the amplitude of the vibrations in dependence on, or a function of, the position of the track;

FIG. 20 is a circuit diagram of a control circuit for simultaneously controlling the downwardly applied pressure and the amplitude of the vibrations in dependence on, or a function of, the position of the track; and

FIG. 21 schematically shows an embodiment of the invention in combination with a track leveling and tamping machine, in side elevation.

Referring now to the drawing, wherein like reference numerals designate like parts operating in a like manner in all figures, FIG. 1 shows a mobile apparatus with a machine frame I mounted on wheels 2 running on rails 6 which, together with ties to which the rails track affixed, form the track. Track sensing elements 3 and 4 are vertically movably mounted in frame 1 at its front and rear ends, respectively, the lower ends of the track sensing elements engaging the track while their upper ends carry a reference line, for instance a tensioned wire 5. In the illustrated embodiment, the track sensing elements are bogies whose wheels run on the track rails and which carry poles on whose tops rollers are mounted over which the tensioned wires 5 are trained. As is well known, reference wires 5 serve as a reference for determining the desired traack level.

A measuring device 7 is mounted on frame 1 to measure the vertical distance between each rail 6 and its associated reference wire 5. For this purpose, the upper end of measuring device 7 carries a sensor for sensing the level of reference wire 5. This sensor may be, for instance, a wire engaging element, such as a fork or a roller, connected with a potentiometer. The potentiometer is adjusted mechanically by the reference wire or by servomechanical means whenever there is a change in the distance between a rail and its associated reference wire. The amount of adjustment of the potentiometer is a measure of the change in distance, as is more fully descried in U.S. Pat. No. 3,547,039, dated Dec. 15, I970.

The lower end of measuring device 7 is affixed to pressure roll 8 which is pressed against the associated rail 6, for instance by hydraulic ram 9 which exerts a vertically downward pressure on the roll. In this manner, the pressure roll follows the rail and transmits any changes in the distance between the'rail and the associated reference wire, due to a faulty track level, to, the measuring device to actuate the potentiometer in the indicated manner.

Double-beveled or flanged wheels 11 are mounted on the machine frame to grip associated rail 6 (see FIGS. 9 to 13) and to hold each railfor substantially horizontal movement therewith, wheels 11 being arranged in pairs, with one wheel in front and the other wheel in back of pressure roll 8, preferably equidistant therefrom. A-hydraulic motor 10 is associated with each wheel 11 to apply a downward pressurethereagainst to maintainthe engagement between the wheels and their associated rails. A vibrator means (not shown) is associated with wheels 11 and arranged to impart vibrations or oscillations in a substantially horizontal direction transverse of the track to the wheels. Since hydraulic motors l0 assure gripping engagement of wheels 11 with rails 6, the substantially horizontal vibrations or oscillations are imparted to the track, ie the two rails affixed to the ties. Preferably, the vibrations imparted to the track will have the same or about the same frequency as the natural or characteristic frequency of vibrations of the track, for instance 8 to 13 cycles per second.

Mounted immediately behind the rear vibratory wheels 11 isa track lining unit 12 of generally conventional type and, therefore, illustratedv only schematically. Such a unit includes track gripping rollers connected to a hydraulic motor for shifting the rollers laterally for lining the track. I

The use of double-beveled whels defining asubstantially V-shaped peripheral groove engaging the rails enables the wheels to be used with rail heads of different widths and this assumes constant gripping of the track rails during the continuous advance of the apparatus over a long stretch of track. Since the railgripping wheels are pressed down against the'rails, the horizontal vibrations cannot cause disengagement of the wheels from the rails.

In essence, the apparatus of FIG. 2 hasthe same structure as that of FIG. 1 described hereinabove. Swivel trucks 2, 2' mounted machine frame 1 for mo-.

respective pair of wheels 14, 14 so that the wheels are pressed vertically downwardly against the track rails. In

this manner, the carwheels 14, 14 operate-in the sameway as pressure rolls 8 to exert a downward pressure on the track. A pair of double-beveledor flanged wheels 17 are journaled on 'axle 18 intermediate the pressure wheels 14, 14, preferably equidistant therefrom, the axle being mounted on car frame 16 (see FIG. 4). Vibrator means 19, suchas rotating unbalanced. weights, are mounted on axle 18, the main componentof the vibrations caused by this means extending in a substantially horizontal plane. These vibrations are transmitted from the axle by wheels 17 to the track. v

As shown inFlGSt2 and 3, auxiliary car 13 carries a measuring device 7associ'ated with each wheel 14 for 6 measuring the distance between the track and the reference line 5 at each wheel. In this manner and as will be explained hereinbelow, the downward pressure exerted upon the track by hydraulic motors 15 through wheels 14 may be controlled at different track points in dependence on the position of the track at these points.

Inthis embodiment, too, a track lining unit 12 is mounted on frame 1 behind the arrangement for exerting a downward pressure and a horizontal vibration upon the track.

FIGS. 5 to 8 show a specific embodiment of an auxiliarycar, such as used in the embodiment of FIG. 2. The car comprises essentially a frame 16 of rectangular or quadratic shape which carries a pair of axles 20 on whose ends wheels or pressure rolls 14 are journaled.

Pivots 21 are mounted on car frame 16 vertically above axles 20, 20, the outer ends of the piston rods of hydraulic rams 15, 15 being affixed to the pivots while the opposite ends of the hydraulic ram cylinders are affixed to pivots 22 which are mounted on machine frame 1, each axle 20 and pivots 21, 22 lying in a vertical plane extending transversely of the track. Hydraulic rams 15 not only exert a downward pressure on wheels 14 of the auxiliary car but also serve for the vertical adjustment in respect of the longitudinal axis of the track on each sidethereof, the weights of each pair rotating in opposite directions, as indicated by the arrows in FIG. 8.

Bearing boxes 27 are mounted on each end of the carrier 24 and double-beveled wheels 28 are journaled in the bearing boxes. Fluid pressure motors 29 are linked; between the carrier and machine frame 1 to exert downward pressure on wheels 28 as well as toenable the carrier to be vertically reciprocated by swinging links 25, 25 up and down. The links 25 are sufficiently resilient in a transverse direction to permit carrier 24 to be swung slightly in a direction transverse to the track so that its horizontal vibratory forces are kept from auxiliarycar frame 16.

Coupling. rods 30 connect the auxiliary car to machine frame 1 to prevent the car from moving in forwardly or backwardly in the direction of track elongation when the hydraulic rams l5 exert a downward pressure on the track' Each measuring device 7 includes a vertical pole 31 pivoted to the car frame 16 and moving vertically with it in response to the track position at the track point engaged by a respective wheel 14.

Since it is the purpose of the present invention to fix the track at a desired level by subjecting it to horizontal vibrations and pressing it downwardly to the desired level, the arrangement of the means for transmitting thedownward pressure and the vibrations to the track and thus to the ballast therebeneath is of special importance. In this respect, the mounting of these means on an auxiliary car, as shown inFIGS. 2 to 8, is particularly useful because this enables the vibrations to be kept away from the main frame of the mobile apparatus and any sensitive measuring instruments mounted thereon. In addition, the auxiliary car, being relatively small and light, can better followthe track andthus increases the 7 accuracy of the measurements of the distance between the track and the reference line, which determine the accuracy of the leveling operation.

It is particularly useful to superimpose a dynamic component upon a static component of the downward pressure force so that the track is subjected to a pulsating stress in a vertical direction. This is accomplished most advantageously in the manner illustrated in FIG. 7 wherein a vibrator 33 constituted by a rotating unbalanced weight is mounted in the line of the downward pressure force exerted by hydraulic ram 15. In this manner, the dynamic force of vibrator 33 is arithmetically added to the pressure force of motor without uncontrollable lateral movements or vibrations.

As shown in FIG. 7, the lower end of hydraulic ram 15 is supported by a spring means 32, for instance a cup spring, on vibrator 33 which is mounted directly on frame 16 of the auxiliary car. The interposition of the spring means has the advantage of keeping vibrations away from machine frame 1.

If desired, more than one vibrator may be arranged between the pressure means 15 and the car frame 16 so that only vibrations in a horizontal direction are transmitted to the frame. If the maximum vibratory force is chosen to equal the pressure force of ram 15, the track will be subjected to a pulsating stress between zero and twice the pressure of ram 15. In this manner, considerable pressure may be exerted upon the track without unduly increasing the weight of the machine.

As shown in FIG. 7, the upper end of pole 31 of measuring device 7 is glidably guided in a bushing in frame 1 and carries potentiometer 72 which is adjusted by a fork 71 holding the reference wire 5, the potentiometer producing a control signal corresponding to the track position in a manner well known in track leveling operations.

FIG. 8 illustrates a hydraulic motor 29 associated with each bearing box 27 so that each wheel 28 is pressed against the rail head it grips. Each bearing box carries a transverse block 34, the inner ends of blocks 34 being interconnected by connecting block 35 which is pivoted to the transverse block ends at 36. This arrangement makes it possible for the wheels 28 to adapt to changes in the track gage (see also FIG. 13).

FIGS. 9 to 14 show modifications of means for transmitting horizontal vibrations or oscillatory forces to the track, such means being adaptable to vary track gages and changing widths of the rail heads.

While it would be possible to use only a single double-beveled wheel for the transmission of the horizontal vibrations to the track, it is preferred to use at least one such wheel for each rail so that both rails may be vibrated simultaneously and thus to relieve undue pressure on the fastening means which attach the rails to the ties.

The simplest vibration transmitting means is illustrated in FIG. 9 wherein two double-beveled wheels 41 are joumaled on transverse axle 40 at a fixed distance from each other. The V-shaped peripheral grooves of the wheels have a relatively small apex angle and the rail heads are received in these grooves with some play. Vibrating means 42 is arranged to impart a horizontal oscillation to axle 40, this oscillation being transmitted by wheels 41 to rails 6. As indicated by the arrows, the vibrating means comprises a pair of unbalances rotating in opposite directions so that the vertical vibrations are substantially eliminated and only the horizontal vibratory components remain. Since the rail heads are 8 received in the wheel grooves with play, this arrangement will adapt to varying widths of the rails heads as well as small changes in the track gage.

In the embodiment of FIG. 10, two parallel transverse axles 40 are spaced from each other. The opposite ends of the adjacent axles carry double-beveled wheels 41 gripping a respective one of heads of rails 6 while the other end of each axle carries a smooth roller 43 running on top of the rail heads. The wheels and rollers are mounted on the axles at a fixed spacing but since the axles are laterally movable independently of each other, this arrangement permits a much wider adaptation to varying track gages than the embodiment of FIG. 9. The axles may, if desired, be joumaled in a frame which is laterally movable. Such gage changes will not influence the transmission of vibrations from the axles to the track due to changes in the track gage.

In the illustrated embodiment, vibrating means 42 are mounted on each axle 40 to impart horizontal vibrations thereto in a manner described in connection with FIG. 9 but care must be taken for the two vibrating means to rotate synchronously and in the same phase so that the same vibratory force is exerted upon both rails of the track. It would be possible, of course, to replace the two separate vibrating means by a single vibrator arranged to impart horizontal oscillations to both axles simultaneously.

FIG. 11 shows another modification of vibration transmitting means useful for the adjustment to variations in the track gage. A single transverse axle 40 carries two double-beveled wheels 41, 41', wheel 41 being mounted on the axle against transverse move ment in relation thereto while a hydraulic motor enables the wheel 41' to be transversely moved along the axle for changing the distance between the wheels and thus to adapt them to different trackgages.

The hydraulic motor comprises a cylinder 44 whose end walls define aligned bores through which axle 40' passes in a fluid-tight manner, wheel 41' being carried by the cylinder. The cylinder is glidably mounted on collar 45 of axle 40'. The collar functions as a piston when pressure fluid is delivered to, or removed from, the cylinder chambers through conduits 46 and 47, the flow of the pressure fluid moving the cylinder laterally on the axle. To avoid interference with the transmission of the vibrations produced by vibrating means 42 from axle 40 to the wheels and the track rails gripped thereby, a stop device 48 is provided to hold the wheel 41' in an adjusted position. This device consists essentially of a two-way solenoid valve which can be moved into a stop position which prevents delivery or removal of pressure fluid from the cylinder chambers so that there can be no relative movement between piston 45 and cylinder 44.

In the embodiment of FIG. 12, the double-beveled wheels 41 are jounaled in the lower ends of carrier arms 50 which are pivotal intermediate their ends about fulcrum axes 51 extending substantially in the direction of the track to enable the carrier arms to be pivoted in a vertical plane transverse to the track. The upper ends of the carrier arms are linked to doubleacting, pressure fluid operated adjustment device 52. By delivering and/or removing pressure fluid through conduits 53 and 54, the adjustment device will pivot the carrier arms and thus adapt the wheels 41 to variations in the track gage.

While the fulcrums 51 may be mounted on boxshaped carrier 24 of the auxiliary car 13 (see FIGS. 5 to 8), if desired, it is preferred, as shown in FIG. 12, to couple the fulcrums by a rigid carrier 55 for vibrating means 42 while the upper ends of the carrier arms 50 are guided in slotted guides in the main machine frame. In this manner, the vibratory forces are transmitted to the double-beveled wheels along the main axis so that the carrier arms may oscillate together with the laterally adjustable carrier 55 without the adjustment device 52 being unduly subjected to vibrations.

It would also be possible to connect the vibrator means directly with the carrier arms for the wheels or to mount them directly thereon and to operate them synchronously a. d in the same phase.

Somewhat similarly to FIG. 8, the embodiment of FIG. 13 has two double-beveled wheels 41 mounted on the short arms of two-armed levers 56, 56 which are pivoted intermediate their ends to frame 16 of an auxiliary car, for pivoting in a vertical plane transverse to the track about fulcrums 57. The ends of the other lever arms are linked together by connecting link 58 whose ends are pivoted to the other lever arm ends at 59, 59. This arrangement makes it possible to adapt the wheels to varying track gages, wheel 41 assuming the position indicated in broken lines at the left of the fig ure when the track gage decreases while the wheels swing the other way when the track gage becomes larger. Vibrating means 42 are mounted on the car frame to impart horizontal oscillations to the wheels.

In the embodiment of FIG. 14, horizontal vibrations are transmitted to the track in a manner similar to that of FIG. 12, but, instead of being transmitted to the track rails, as in the embodiments of FIGS. 9 to 13, they are transmitted to the ends of the track ties. This embodiment is particularly useful when concrete ties are used.

As will be seen in FIG. 14, carrier arms 60, 60 are spaced apart a distance corresponding roughly to the length of the ties and are pivotal in a vertical plane transverse to the track about fulcrums 61, 61. Pressure fluid operated adjustment devices 62, 62 are linked to the upper ends of the carrier arms while the lower carrier arm ends have pressure plates 63, 63 which may be pressed against the tie ends by operation of the adjacent devices. Fulcrums 61 are connected by rigid carrier 64 to which horizontal vibrations are imparted by vibrator 65 which, in the illustrated embodiment, has the form of an eccentric shaft. The entire vibrating arrangement may be vertically adjusted by means of hydraulic motors 66.

It is one of the essential features of the present invention to couple the reference system, i.e. the means for surveying and indicating the level of the track, with the means for downwardly pressing and horizontally vibrating the track so that the operating parameters may be controlled so as to reposition the track at the desired level. Therefore, the apparatus comprises a reference system which includes a measuring device for ascertaining the difference between the actual and the desired track level, which is well known per se in the track leveling art, and operatively coupled thereto a control circuit responsive to the track level measurements for actuating the downward pressure and horizontal vibrating means in dependence on, or a function of, error signals produced by the measuring device at successive track points.

FIGS. to 20 illustrate different embodiments of such controls enabling selected operating parameters for the track leveling operation, such as the downward pressure force, the frequency and/or amplitude of the horizontal vibrations, and the duration of the pressure and/or vibrations, to be controlled in dependence on an initial error signal, i.e. an initial measurement of the distance between the track and the reference line which indicates a deviation from the desired track level, or on continuous and successive error signals corresponding to successive track points traversed by the continuously advancing machine.

The circuit diagram of FIG. 15 shows a control enabling the downward pressure force exerted upon the track to be controlled in response to a continuous measurement of the difference between the actual and the desired track level. This control circuit comprises a bridge circuit which includes potentiometer 72 (see FIG. 7) whose output signal is adjusted by fork 71 which holds reference wire 5 and, therefore, is moved in dependence on the wire position, i.e. its distance from the actual track level. Thus, the output voltage of the potentiometer is proportional to the actual track level as compared to the desired level which is set by the reference wire. The resultant output signal of bridge circuit 70 and a signal corresponding to the desired track level are compared in amplifier 73. The resultant reference signal is ampified in the amplifier and forms the output signal of the amplifier, which is proportional to the difference between the actual and the desired track levels. The amplified output signal is transmitted to solenoid valve 74 which is continuously adjustable to control and adjustment of the valve in response to the measured track level error. Valve 74 is arranged in the hydraulic fluid flow circuit delivering hydraulic fluid to the downward pressure applying motors, for instance hydraulic motors 9 or 15 (FIGS. 1 and 2), to control the hydraulic fluid delivery, i.e. the pressure, in proportion to the amplified control signal coming from bridge circuit 70 and amplifier 73.

The hydraulic fluid flow circuit comprises a hydraulic fluid sump whose fluid delivery line is connected to the input of constant speed pump extent The output of the pump leads to slide valve 76 which controls the fluid flow to rams 9 or 15 so that it stops fluid delivery entirely when the control signal is zero, i.e. the track has reached the desired level, while the fluid flow is varied by valve 74 in response to variations in the control signal. A signal indicator 77, such as an amperemeter, is arranged in the electrical circuit between amplifier 73 and valve 74 so that the size of the control signal may be read by an operator who is thus enabled to see the extend of the required tract repositioning.

While the control signal, which is proportional to the track level error signal, has been used to control the downward pressure on the track in the embodiment of FIG. 15, FIGS. 16 and 17 illustrate control circuits which control the frequency of the horizontal vibrations imparted to the track in response to such control signals. In these embodiments, the structure and operation of circuit elements 70 to 73 are identical to those of FIG. 15, the embodiment of FIG. 16 also providing amperemeter 77.

In the control circuit of FIG. 16, the control signal is transmitted to valve 80 to control the amount of hydraulic fluid flowing through hydraulic fluid circuit 81. The circuit 81 includes the constant speed pump which receives hydraulic fluid from hydraulic fluid sump 83 wherein the hydraulic fluid is held at atmospheric pressure, and also hydraulic motor or motors 82 which drives or drive the vibrating means for imparting horizontal oscillations to the track. The output of motor or motors 82 is proportional to the hydraulic fluid throughout in circuit 81 controlled by valve 80, i.e. proportional to the control signal, the changing motor output correspondingly varying the horizontal oscillations or vibrations. For instance, if the frequency of the vibrations was near the resonance point of the track at the beginning of the operations at a given difference between the actual and the desired track levels, it will be changed away from resonance as the track level approaches the desired level.

In the control circuit of FIG. 17, the frequency of the vibrations is controlled only by electrical means. Here again, the structure and function of circuit elements 70 to 73 are identical with those of FIG. and, therefore, require no further description. However, the hydraulic fluid circuit 81 of FIG. 16 is replaced by electrical circuit 90. Direct current drive motor 91 for the vibrating means is arranged in shunt in circuit 90. The control signal is transmitted from amplifier 73 to drive motor 94 which moves sliding contact 93 of variable resistance 93 in circuit 90 so that the power supplied to field coil 92 of direct current motor 91 is changed in proportion to the control signal. This changes the rotational speed of drive motor 91 and correspondingly the frequency of the vibrations produced by the vibrating means driven by motor 91. If the control signal were sufficiently amplified in amplifier 73, it could be used directly for the adjustment of variable resistance 93 without interposition of motor 94.

FIGS. 18, 19 and show controls for changing the amplitude of the horizontal vibrations in response to the error signal by switching a selected number of vibrators on or off.

Referring to the circuit diagram of FIG. 18, two separate control circuits I and II are provided for operating drive motors 100 and 101, respectively, for the vibrating means. The two control circuits are closed, i.e. power is fed to the drive motors, by closing switches 102 and 103, respectively. Opening and closing of the switches is controlled by switch tripping relays 104 and 105, respectively which are operated mechanically directly by caming surfce 106 affixed to the pole of measuring device 7. The distance between the camming surface 106 and reference wire 5 is constant. Switch tripping relays 104, 105 are mounted on rolls 8 or 14 (see FIG. 1 and 2) so that the position of the camming surface 106 in relation to relays 104, 105 will depend on the level of the track.

If the actual track level is above the desired track level within a predetermined normal range of magnitude, camming surface 106 will actuate only relay 105 (as shown in FIG. 18) so that only control circuit I is closed to operate the vibrating means drive motor 100. However, if the actual track level is particularly high so that increased force is desirable for pressing the track down to the desired level, camming surface 106 will also actuate relay 104 to operate motor 101 in control circuit II. This will increase, for instance double, the amplitude of the vibrations.

Substantially the same operating principle is essentially followed in FIG. 19, except that the electrical control circuits I and II are replaced by hydraulic fluid circuits 1' and II. In this embodiment, camming surface 106 is mounted on the pole or measuring device 7 and remains at a constant distance from the rail on which the pole for measuring device 7 rides. Relays 104, 105 are mounted on the frame of the apparatus or on pressure rolls 8 or 14 and will be sequentially tripped as the pole rises. Sequential operation of the relays will sesquentially operate solenoid slide valves 112 and 113 placed in the respective hydraulic fluid circuits delivering oil from sump 111 to constant speed pumps 109 and 110, respectively, supply of hydraulic fluid operating hydraulic drive motors 107 and 108, respectively, for the vibrating means. Thus, the extent of the re quired correction stroke for pressing the track down to the desired level controls the operation of the vibrating means in the manner described in connection with FIG. 18.

FIG. 20 shows a control circuit diagram for controlling the stepwise actuation of additional vibrators for increasing the vibration amplitude as well as addditional hydraulic rams for increasing the downward pressure on the track in proportion of the length of the correction stroke required to reposition the track at the desired level.

The control circuit elements to 73 are again the same as those described in connection with FIGS. 15 to 17, providing a control signal at the output of amplifier 73 which is proportional to the track level error. This error signal is transmitted to computer which classifies the signal into individual signal steps, the illustrated embodiment providing three signal steps, the three resultant output signals of computer 120 operating solenoid slide valves 121, 122 and 123 which control hydraulic drive motors 124, 125 and 126 sequentially, the valves and associated drive motors being arranged in three separate hydraulic fluid circuits. The drive motors operate the vibrating means. Furthermore, hydraulic rams 130, 131 and 132 for experting downward pressure on the track are also mounted in the respective hydraulic fluid circuits, the pressure in the latter motors being controlled by pressure reducing slide valves 127, 128 and 129, respectively. These valves are also controlled by the output signals from computer 120.

If the output signal of amplifier 73 indicates a relatively small track level error, it will be classified only in one step of computer 120. Thus, only a single vibrating means drive motor and a single downward pressure ram will be actuated. As the level error increases, producing an error signal at the output of amplifier 73 proportional thereto, the computer will sequentially actuate the additional vibrating means drive motors and downward pressure rams. A further differentiation in the force applied to the track may be achieved by using vibrators with different amplitudes and rams with different pressures. It would also be possible, of course, to operate the vibrating means sand the downward pressure rams independently by computer 120.

As will be obvious from the above description of certain now preferred embodiments of the present invention, apparatus according to this invention makes it possible to do track maintenance work attuned most sensitively to various requirements and conditions encountered in compacting ballast underneath a track and positioning the track at a desired level. Thus, it is possible to control not only the speed in which the desired track level is reached but also the nature of the ballast tamping. Since these factors depend at least one three parameters, i.e. the downward pressure force, the frequency and the amplitude of the horizontal vibrations to which the track is subjected, variations in these parameters may be variously controlled and coordinated to meet all requirements in a most sensitive manner. Furthermore, in a continuoustrack work opera-.

tion, it is possible to operate the parameters sequentially at any given track point. It is also possible to anticipate an observed track depression of excessive magnitude before this point is reached bylifting the track at this point particularly high.

The invention may be advantageously combined with a mobile track leveling and lining machine of otherwise conventional structure, the track tamping, leveling and lining means being mounted on the machine frame ahead of the means for vibrating the track horizontally and pressing it downwardly, in the, working direction of the machine. v k

An apparatus of this type is shown in 21 wherein an elongated machine frame runs on the track on wheels 2,2, tamping assembly 140 being mounted on an overhanging frame portion whose front holds track jack 141 for leveling and/or lining the track, the leveling beingeffected in relation to reference line A mobile track working machine of this general type is shown, for instance, in US. Pat. No. 3,211,109, dated Oct. 12, 1965, but any other track leveling and/or lining machine may be used. Analogous to the embodimerit of FIG. 2, auxiliary car113 with its gear according the the invention, is mounted intermediate'the machine wheels. I

With a machine of this type, the track may'be'raised by jack 141, at which time it may also be lined by the jack, the ballast may be tamped underneath the ties by assembly 140, and the track is then pressed down to the desired track levelwhile being'horiz oritally vibrated at any selected track point according tothe irivention, the repositioning of the track sijr'nultfaneously causing compaction of the ballast thereunderl' I It will be clearly understood that the present invention is not limited to'the specifically described embodiments thereof. For instance, while one type of measuring device has been described and illustrated, many devices are known and useful for the practice of this invention for indicating a track level error and producing a proportional error signal for controlling track leveling mechanisms. Such devices may work with reference beams of electromagnetic radiation, such as light or laser beams, instead of reference wires, as illustrated herein.

Furthermore, any suitable vibrating means may be used for imparting substantially horizontal vibrations or oscillations to the track, including rotating unbalanced weights, vibrating rams or eccenter shafts. The only essential characteristic of the vibrating means is that it has a marked horizontal component for imparting a substantially horizontal vibration to the track. It is also essential that the means for transmitting the vibrations to the track is so arranged that the track will vibrate with substantially the same frequency and amplitude as the controlled vibration of the vibrating means. the

While hydraulic rams have been illustrated for exerting a static downward pressure on the track, spindledriven or like rams could equally used for this purpose, the type, arrangement and number of rams varying greatly according to requirements and conditions. Any desired dynamic pressure component may be produced not only be the illustrated vibrators but also by other suitable pulsors. Selected combinations of means for producing static and dynamic pressure components will result in pressure forces of a type and magnitude encountered when trains pass over the track. When the force of the downward pressure is controlled by switch- 14 ing on additional rams, the sensitivity of te control will dependon the number. of the rains provided.

While, anumberof controls have been illustrated, this does not exhaust the possibilities. For instance, the controls for thepressure, the frequency and the amplitude of the vibrations may be combined in'any desired manner. Thus, the illustrated control diagrams will be understood to'show only the principles of useful controls.

We have found that track surfacing according to the present invention holds the track at the desired level for a very longpperiod of time since it compacts the ballast to an extent equivalent to that usually accomplished only by long and extensive train traffic and the resultantpressures and vibrations to which the passing trains subject the ballast. Furthermore, such track surfacing also results in a considerable compaction of the ballast at the ends of the ties, which has a most advantageous effect on the lining of the track.

The metes and bounds of the invention are defined by'tl'ie appended claims. I

What we claim is:

1. In a method of surfacing a track consisting of rails fastened to ties resting on ballast, wherein theballast is compacted and the track is simultaneously downwardly displaced to a desired level: the steps: of imparting a substantially horizontal vibration to .a section of the track and simultaneously pressing the track section substantially vertically down until it has reached the desired level. a i

2. In the tracksurfacing method of claim 1, thestep of imparting the horizontal vibration to the track rails.

3 In the track surfacing methodof claim 1 the step of determining the downward stroke required to press the track section down to the desired level, and pressing the tracksection. through said stroke.

4. In the track surfacing method of claim 3, thesteps of first raising the track section and tamping the ballast under the ties of the raised track section before determining the downward stroke.

5. In the track surfacing method of claim 1, wherein the vibration has about the same frequency as the natural or characteristic frequency of vibratons of the track.

6. In the track surfacing method of claim 1, wherein the track section is pressed down by a pulsating stress force.

7. In the track surfacing method of cliam 1, the steps of determining any deviation of the track position from the desired level, producing an error signal proportional to said deviation, and controlling the horizontal vibration in response to the error signal.

8. In the track surfacing method of claim 7, wherein the frequency of the vibration is controlled in response to the error signal.

9. In the track surfacing method of claim 7 wherein the amplitude of the vibration is controlled in response to the error signal.

10. In the track surfacing method of claim 7, wherein the duration of the vibration is controlled in response to the error signal.

11. In the track surfacing method of claim 1, the steps of determining any deviation of the track position from the desired level, producing an error signal proportional to the determined deviation, and controlling the downward pressure on the track in response to the error signal.

12. In the track surfacing method of claim 11, wherein the force of the pressure is controlled in re- 1s sponse to the error signal.

13. In the track surfacing method of claim 11, wherein the duration of the pressure is controlled in response to the error signal.

14. In the track surfacing method of claim 1, wherein the ballast compaction and the downward track positioning are effected at sequential track points along the track in a continuous manner.

15. In the track surfacing method of claim 14, the step of continuously determining any deviation of the track position from the desired level during the continuous ballast compaction and downward track displacement.

16. In the track surfacing method of claim 1, wherein the force of the downward pressure on the track section is changed as the track section approaches the desired level.

17. In the track surfacing method of claim 16, wherein the force of the downward pressure is increased as the track section approaches the desired level.

' 18. In the track surfacing method of claim 1, wherein the horizontal vibration and the downward pressure is imparted to the track section at substantially the same pomt.

19. In the track surfacing method of claim 18, wherein the downward pressure is imparted to the track section in stages.

20. In the track surfacing method of claim 1, wherein the horizontal vibration is imparted to the track section in stages at several points along the track.

'21. In the track surfacing method of claim 1, the step of lining the track section while it is leveled.

22. A method of surfacing a track consisting of rails 3 16 the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level, the vibration having a frequency in the range of 8 to 13 cycles per sec- 0nd.

23. A method of surfacing a track consisting of rails fastened to ties resting on ballast, comprising the steps of compacting the ballast under the track ties and simultaneously positioning the track at a desired level, the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level by a pulsating stress pressure force having a static and dynamic component, the dynamic component of the pressure force being an oscillating force whose amplitude does not exceed twice the static component of the pressure force.

24. A method of surfacing a track consisting of rails fastened to ties resting on ballast, comprising the steps of determining any deviation of the track position from a desired level, producing an error signal'proportional to the determined deviation, compacting the ballast under the track ties and simultaneously positioning the track at the desired level, the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pre'ssing the track substantially vertically down to the desired level, and controlling the horizontal vibration and the downward pressure in response to the error signal.

25. In the track surfacing method of claim 1, the step of determining the downward stroke required to press the track section down to the desired level, and pressing the track section through said stroke by a static force of a magnitude determined by the extent of said stroke. 

1. In a method of surfacing a track consisting of rails fastened to ties resting on ballast, wherein the ballast is compacted and the track is simultaneously downwardly displaced to a desired level: the steps of imparting a substantially horizontal vibration to a section of the track and simultaneously pressing the track section substantially vertically down until it has reached the desired level.
 2. In the track surfacing method of claim 1, the step of imparting the horizontal vibration to the track rails.
 3. In the track surfacing method of claim 1, the step of determining the downward stroke required to press the track section down to the desired level, and pressing the track section through said stroke.
 4. In the track surfacing method of claim 3, the steps of first raising the track section and tamping the ballast under the ties of the raised track section before determining the downward stroke.
 5. In the track surfacing method of claim 1, wherein the vibration has about the same frequency as the natural or characteristic frequency of vibratons of the track.
 6. In the track surfacing method of claim 1, wherein the track section is pressed down by a pulsating stress force.
 7. In the track surfacing method of cliam 1, the steps of determining any deviation of the track position from the desired level, producing an error signal proportional to said deviation, and controlling the horizontal vibration in response to the error signal.
 8. In the track surfacing method of claim 7, wherein the frequency of the vibration is controlled in response to the error signal.
 9. In the track surfacing method of claim 7 wherein the amplitude of the vibration is controlled in response to the error signal.
 10. In the track surfacing method of claim 7, wherein the duration of the vibration is controlled in response to the error signal.
 11. In the track surfacing method of claim 1, the steps of determining any deviation of the track position from the desired level, producing an error signal proportional to the determined deviation, and controlling the downward pressure on the track in response to the error signal.
 12. In the track surfacing method of claim 11, wherein the force of the pressure is controlled in response to the error signal.
 13. In the track surfacing method of claim 11, wherein the duration of the pressure is controlled in response to the error signal.
 14. In the track surfacing method of claim 1, wherein the ballast compaction and the downward track positioning are effected at sequential track points along the track in a continuous manner.
 15. In the track surfacing method of claim 14, the step of continuously determining any deviation of the track position from the desired level during the continuous ballast compaction and downward track displacement.
 16. In the track surfacing method of claim 1, wherein the force of the downward pressure on the track section is changed as the track section approaches the desired level.
 17. In the track surfacing method of claim 16, wherein the force of the downward pressure is increased as the track section approaches the desired level.
 18. In the track surfacing method of claim 1, wherein the horizontal vibration and the downward pressure is imparted to the track section at substantially the same point.
 19. In the track surfacing method of claim 18, wherein the downward pressure is imparted to the track section in stages.
 20. In the track surfacing method of claim 1, wherein the horizontal vibration is imparted to the track section in stages at several points along the track.
 21. In the track surfacing method of claim 1, the step of lining the track section while it is leveled.
 22. A method of surfacing a track consisting of rails fastened to ties resting on ballast, comprising the steps of compacting the ballast under the track ties and simultaneously Positioning the track at a desired level, the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level, the vibration having a frequency in the range of 8 to 13 cycles per second.
 23. A method of surfacing a track consisting of rails fastened to ties resting on ballast, comprising the steps of compacting the ballast under the track ties and simultaneously positioning the track at a desired level, the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level by a pulsating stress pressure force having a static and dynamic component, the dynamic component of the pressure force being an oscillating force whose amplitude does not exceed twice the static component of the pressure force.
 24. A method of surfacing a track consisting of rails fastened to ties resting on ballast, comprising the steps of determining any deviation of the track position from a desired level, producing an error signal proportional to the determined deviation, compacting the ballast under the track ties and simultaneously positioning the track at the desired level, the ballast compaction and the track positioning being effected by imparting a substantially horizontal vibration to the track while pressing the track substantially vertically down to the desired level, and controlling the horizontal vibration and the downward pressure in response to the error signal.
 25. In the track surfacing method of claim 1, the step of determining the downward stroke required to press the track section down to the desired level, and pressing the track section through said stroke by a static force of a magnitude determined by the extent of said stroke. 